For those of you who liked the series "The Walking Dead" on A&E last season, it will be back. I''m in Prague with the VFX Supervisor from Stargate Studios who did the visual effects for the show. He turned me onto this Youtube video. Its a good example of how computers are used in motion picture and television, and replacing a lot of actual action and footage in general. At 2:47 in the video look carefully and you can see the nitrogen pressured piston being blown out of the cannon welded into the bottom of the GTO as it flips over. They pressure it to about 150 psi to flip it once and up to about 300 psi to do multiple flips, and varies with the weight of the vehicle of course. Where the piston flies can be dangerous, they are sometimes made of steel, but they are using hard plastic pistons turned on a lathe more and more. The old technology was black powder and a greased piece of telephone pole. Obviously, nitrogen with a pressure gauge is more reproducible with testing then measuring out black powder.
http://youtu.be/klGw_8Ia6Vs
How do you embed a video, I clicked on embed and it gave me that link which I pasted in?